Boy, 5, missing in the Murray, another child savaged, woman arrested

A woman is expected to be charged with attempted murder over the death of one of her sons at Moama, on the New South Wales-Victoria border, as police continue to search for his younger brother after an incident on the Murray River last night.

When asked what the chances were the five-year-old would be found alive, Supt Condon said: "There is every chance". Victorian Police divers have also been searching the river.

Deniliquin police Superintendent Paul Condon said the dog belonged to a Moama family and police and emergency services were contacted by a local resident about the incident.

Police divers spent Friday combing the Murray River in Moama for the missing boy but were forced to call off the search due to failing light.

But officers are still scouring the river searching for the unnamed woman's five-year-old who was allegedly seen drifting face down in the water.

The woman was being questioned by police on Friday, a NSW police spokesman said.

The owner of a dog, which attacked a nine-year-old boy and his 27-year-old mother, says the pit bull was actually trying save the boy from drowning.

"It is a bad story".

He reportedly attacked the mother, creating an opportunity for the elder child - who was also bitten badly in the altercation - an opportunity to escape.

The child's 27-year-old mother, who was arrested after presenting herself to Victoria police on Thursday night, has been released and is assisting detectives with their inquiries.

The older boy has been transferred to hospital in Melbourne after initial treatment at Echuca.

The Riverine Herald has reported police have already recovered a small T-shirt from the river.

A search by NSW and Victoria police, SES and Maritime Rescue began on Thursday evening but was called off at 11pm, before being restarted at 8am on Friday.

"We've had a brief conversation with the nine-year-old last night and we haven't had another".

"I think it will rock the community of Australia", he said.

"He required some surgery on the dog bites at this stage and of course, he is distressed".

Further murder charges could be laid against the woman depending on the results of the search.

"It's devastating. My police are devastated, the community is devastated".